Crosslink formation between DNA and nuclear proteins by in vivo and in vitro exposure of cells to dimethylarsinic acid

DNA damage induced by arsenics, particularly by dimethylarsinic acid (DMAA), a main metabolite of inorganic arsenics in mammals, was investigated. DNA-protein crosslinks, similarly to DNA single-strand breaks, were induced in mouse and human culture cells by the treatment with DMAA. The crosslinks were sensitive to treatment with guanidine and hydroxylamine, suggesting that the DNA linkage sites in proteins were serine and threonine residues of H1 histone and of nonhistone proteins and that the linkage occurred through a phospho-nitrogen bond. The type of crosslinks was different from that induced by X-ray radiation. Of the radicals produced in the further metabolic processing of DMAA, the dimethylarsenic peroxyl radical rather than the superoxide anion radical is likely responsible for the formation of crosslinks, similar to the case of DNA single-strand breaks.

[A case of medically treated type A acute aortic dissection: trial of antifibrinolytic therapy while monitoring the thrombotic and fibrinolytic parameters]

A 56-year-old male was admitted with severe chest and abdominal pain. Enhanced CT revealed type-A acute aortic dissection. Enhancement of false lumen was complete in the aortic arch, but it was incomplete in the ascending and descending aorta. This finding suggested a thrombosing tendency of the false lumen. Marked elevation of Thrombin-Antithrombin III complex (TAT) and Plasmin-alpha 2 Plasmin inhibitor complex (PIC) indicated the activation of both coagulation and fibrinolysis in the false lumen. Aprotinin and Tranexamic acid were used in order to suppress the fibrinolysis. Both TAT and PIC were completely normalized at the 20th hospital day. Enhanced CT on the 40th hospital day showed that the false lumen had disappeared, and the adventitia had thickened. Care should be taken to notice activated coagulation and fibrinolysis in the false lumen. This report appears to be the first statement about the effectiveness of antifibrinolytic therapy to facilitate thrombosing and healing of the false lumen in the treatment of acute aortic dissection.

[A successful surgical case of thoracoabdominal aortic aneurysm ruptured into the right pleural cavity]

A 55-year-old man was transferred to our cardiovascular center because of right hemothorax and hemorrhagic shock. Emergency CT scan revealed a thoracoabdominal aortic aneurysm (Crawford's type I-A) ruptured into the right thorax. The aneurysm was exposed by Stoney's spiral opening approach. A 24 mm Cooley Dacron graft was implanted in end-to-end fashion between the descending thoracic aorta and the abdominal aorta just above the celiac artery. The use of aortic artery cannula, femoral artery cannula and flexible polyvinyl tube provided safe and simple means as a temporary bypass during this graft replacement. Postoperative course was uneventful.

Investigation of germinative cells in generating and renewed anagen hair apparatus in mice using anti-bromodeoxyuridine monoclonal antibody

To elucidate the cell kinetics in generating and renewed anagen hair apparatus in mice, S-phase cells in dorsal skin of new-born and 14 to 25-day-old mice were labeled with bromodeoxyuridine (BrdU) and stained immunohistochemically using anti-BrdU monoclonal antibody. In primary hair germ, lower and outer cells were positively stained. In hair peg, the positive cells were divided into upper and lower portions. In bulbous hair peg, the lower positive cells gathered at the suprapapillary area, whereas the upper positive cells were located in the outer part of the hair apparatus. The latter positive cells were further divided in the middle and upper parts of the epithelial cord. The upper cells were going to form a sebaceous gland. From the suprapapillary group of germinative cells, hair cortex through the innermost cell layer of the outer root sheath were considered to be produced. The positive cells of the outer middle group may be important for elongation of hair apparatus and produce outer root sheath cells. At the end of anagen phase, first the suprapapillary cells became negative and then the outer root sheath cells became negative. BrdU-positive cells reappeared at the bottom of telogen hair apparatus and formed a secondary hair germ. Then, a similar cell kinetics was repeated in the renewed anagen hair apparatus. The germinative cells were separated into a few groups during the generation and cyclic changes of hair apparatus. Each cell group formed the individual part of the hair apparatus in a coordinate fashion, resulting in dynamic changes of the hair apparatus.

Chromium (III) decreases carbon tetrachloride-originated trichloromethyl radical in mice

Effects of the administration of trivalent chromium (Cr(III)) to mice and the activation of carbon tetrachloride (CCl4) to form trichloromethyl radicals (.CCl3) in the liver were studied. The lipid peroxidation in liver microsomes induced in vitro by CCl4 in the presence of NADPH was decreased by the preadministration of Cr(III) to mice. The activity of NADPH-cytochrome C reductase, which presumably catalyzes the formation of .CCl3 from CCl4 in liver microsomes, was depressed by Cr(III) administration and kept at a level lower than that of the control group for at least 2 hr after CCl4 dosing. Furthermore, the frequency of appearances of ESR signals of .CCl3 in the liver homogenate of mice 1 min after CCl4 administration was markedly decreased by Cr(III) preadministration, similarly to DL-alpha-tocopherol. These results suggest that Cr(III) preadministered to mice decreases the formation of .CCl3 from CCl4, an activating process of CCl4, in the liver, presumably by scavenging the radical.

Histopathogenesis of inflammatory linear verrucose epidermal naevus: histochemistry, immunohistochemistry and ultrastructure

Skin lesions of three patients with inflammatory linear verrucose epidermal naevus (ILVEN) were examined. Histologically, orthokeratosis and parakeratosis were alternately seen in the acanthotic epidermis. By N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide staining, the horny cells in the parakeratotic epidermis showed a cytoplasmic SH pattern and a weak membranous SS pattern. The orthokeratotic epidermis revealed an increased involucrin expression, whereas the parakeratotic epidermis showed almost no involucrin expression. Ultrastructurally, in the parakeratotic epidermis, the living keratinocytes had prominent Golgi apparatuses and vesicles in the cytoplasm. In the intercellular spaces in the upper spinous layer through to the lower horny layer, an electron dense, homogeneous substance was deposited. The cytoplasm of the horny cells was filled with keratin filaments and contained remnants of nucleus and cytoplasmic membrane structures, and some lipid droplets. The marginal band formation was incomplete. Most of these ultrastructural abnormalities were not found in the orthokeratotic epidermis. There are both similarities and differences in histopathogenesis of the parakeratotic epidermis between ILVEN and psoriasis. A unique finding was the lack of involucrin expression in the ILVEN parakeratotic epidermis.

Differential analysis of the human anagen hair apparatus using lectin binding histochemistry

Cell differentiation in the human anagen hair apparatus was examined by lectin-binding histochemistry using seven different lectins: Con A, WGA, RCA-I, PNA, SBA, DBA and UEA-I. Con A and WGA positively stained almost all the cells in the hair apparatus. RCA-I and PNA positively stained the outer cells of the outer root sheath (ORS), but they did not stain the innermost cells (IMCs) of the ORS in the suprabulbar region. However, in the isthmus region, the IMCs showed positive staining with RCA-I, and more intense staining with PNA than that of the outer ORS cells. The ORS cells, including the IMCs, were negative with SBA and DBA below the suprabulbar region, whereas the IMCs became more strongly positive with these two lectins than the other ORS cells in the isthmus region. UEA-I strongly stained the IMCs, but not the outer ORS cells in the hair bulb. The latter cells became positive for UEA-I above the suprabulbar region. These findings indicate that the surface glycoconjugate distribution of the IMCs differs from that of the outer ORS cells. It is concluded that the IMCs of the ORS may undergo an independent cell differentiation process.

Protective effect of chromium(III) on acute lethal toxicity of carbon tetrachloride in rats and mice

Trivalent chromium (Cr(III)) preadministered intraperitoneally (5 mg Cr/kg body weight) to rats and mice protected these animals from acute lethal toxicity of carbon tetrachloride (CCl4). Some other metals, Cr(VI), Cu(II), and Zn(II), had no effect on CCl4 lethal toxicity. DL-alpha-tocopherol, one of the antioxidative agents, showed similar protective effects to Cr(III). Activities of serum GOT and GPT in mice were increased sharply by the administration of CCl4, but these elevations were depressed by Cr(III) preadministration. Serum glucose levels of mice increased transiently after CCl4 administration and then in the control group fell to hypoglycemic levels after 6 hr, whereas the Cr(III)-pretreated group kept to homeostatic levels. Lipid peroxidation of microsomes in mice 24 hr after Cr(III) administration was lower than that of the control. These results suggest that Cr(III) preadministered to mice might act as a radical scavenger to CCl4 to form trichloromethyl radicals which are a major initial product of CCl4 in liver cells.

[Adenosquamous carcinoma of the skin--ultrastructural and immunohistochemical studies]

Adenosquamous carcinoma, which arose on the face of a 83-year-old woman was studied ultrastructurally and immunohistochemically. The tumor was composed of squamoid cells and mucinous cells including signet-ring cells. Electron microscopically, the tumor cells developed numerous microvilli on the cell surface, and had tonofilaments, well-developed rough endoplasmic reticulum and secretory granules of a mucinous type in the cytoplasm. The signet-ring cells had a large intracytoplasmic cavity containing fine fibrillar, mucin-like substance. Occasionally observed were intercellular masses, around which the tumor cells formed hemidesmosome-like and basal lamina-like structures. Immunohistochemical staining revealed foci of positive reaction for laminin surrounding the tumor cells. The tumor cells displayed positive stainings for stratified-epithelial keratins, but not for simple-epithelial keratins. From these findings, it was concluded that the present tumor might be a carcinoma of squamous cell origin, showing a mucinous metaplasia.

[The indication and effects of palliative right ventricular outflow tract reconstruction for tetralogy of Fallot with pulmonary atresia]

Palliative right ventricular outflow reconstruction (RVOT) in 5 cases with tetralogy of Fallot with valvular pulmonary atresia and 5 cases with truncal pulmonary atresia were studied regarding indication and postoperative development of pulmonary artery. In 4 cases with valvular atresia, RVOT was performed following previous palliation such as Blalock-Taussig shunt, and resulted in improvement in clinical symptoms and in significant increase in postoperative PA-index from 105.4 mm2/m2 before operation to 159.4 mm2/m2. In one case, RVOT was performed as the first stage palliation and symmetrical development of pulmonary arteries were observed. All underwent successful total correction later. However, in 5 cases with the truncal atresia, 2 died after RVOT and postoperative development of pulmonary artery was insignificant. RVOT is indicated for cases with poor pulmonary arterial development despite of palliation, and in future, RVOT as an initial palliation will be indicated in infants with hypoplastic pulmonary artery.

Cell kinetic study of human and mouse hair tissues using anti-bromodeoxyuridine monoclonal antibody

To determine sites of cell proliferation in hair tissues, in vitro and in vivo labeling with bromodeoxyuridine (BrdU) and immunohistochemical demonstration of BrdU incorporation sites by anti-BrdU monoclonal antibody were performed on human and mouse hairs and hair follicles. The germinative area of the hair bulb of human anagen hair was divided into three portions: (A) the upper and inner portion, (B) the middle portion and (C) the lowest outer portion. A-cells intermingled with melanocytes, were regarded as germinative cells of the hair cortex. B-cells appeared to develop into Huxley's layer, cuticle of inner root sheath (IRS), and hair cuticle. C-cells seemed to develop into bulbar outer root sheath (ORS), the innermost cell (IMC) layer of the ORS and Henle's layer. The suprabulbar portion, where the ORS abruptly increased in thickness, was found to be the fourth main germinative portion (D). The ORS cells, except for the IMCs, seemed to originate mostly from the D-cells. In the late anagen phase, first, C-cells became BrdU negative, then, A- and B-cells gradually turned negative, and finally, D-cells lost their germinative activity. In catagen and telogen hair tissues, BrdU-positive cells were found in the two outer cell layers in the ORS. The structure of anagen hair tissues seems to be maintained by the coordinated mitotic activities of characteristically distributed germinative cells of various hair cell layers. The sequential cessation of mitotic activity of these cells is associated with the morphological changes from anagen through catagen to telogen. These findings were common to both human and mouse hair tissues.

The fine structure and elemental analysis of keratinized epithelium of the filiform papillae analysis on the dorsal tongue in the American alligator (Alligator mississippiensis)

The filiform papillae of subadult alligator (120 cm-260 cm total length) tongues are examined by scanning electron microscopy and electron microprobe analysis. The filiform papillae form cone-like structures and are observed over the entire dorsal surface of a relatively long tongue with a round tip. The filiform papillae are composed of four layers; outer, upper intermediate, lower intermediate, and basal layer. The keratinized epithelial cells are analysed by the sulphur (S), and nitrogen (N) content levels. The S content is higher than that of N. In the anterior side of the filiform papillae, this content is lower than that in the posteriors. The S content is highest of all at about 2 microns in depth from the surface. These results suggest that the use of S concentration measurements may serve to be an effective tool for a simple, offhand evaluation of keratinization.

Effect of nucleotide substitution on the peptidyltransferase activity of 2'(3')-O-(aminoacyl) oligonucleotides

Seven 2'(3')-O-(aminoacyl) trinucleotides with structures derived from the 3'-terminal C-C-A sequence of aa-tRNA via nucleotide substitutions were investigated as acceptor substrates in the peptidyltransferase reaction and as inhibitors of substrate binding to the peptidyltransferase A site. It was found that all tested compounds were active in both systems, although substitution in the first and second nucleotide position results in some decrease of acceptor activity. Remarkably, replacement of natural cytidylic acid residues in C-C-A-Phe with guanylic acid moieties resulted only in a small decrease of acceptor or binding activity. The results indicate that the acceptor sequence of aa-tRNA is not probably engaged in base pairing with a sequence of 23S RNA during its interaction with the peptidyltransferase A site.

[Surgical experience with an infant with discrete subaortic stenosis successfully treated by aortoventriculoplasty]

A 3-year-old female with discrete subaortic stenosis is presented. Angiocardiographic studies showed a long segmental narrowing below the aortic valve. Although membranectomy and myectomy were selected as a surgical treatment, a longitudinal aortotomy was performed in order to extend the operation to ventriculoseptoplasty. During the operation, the right coronary cusp was seriously damaged and therefore aortoventriculoplasty was applied. The aortic valve was replaced with a 21 mm St. Jude Medical mechanical prosthesis. The left ventricular outflow tract was adequately enlarged, and postoperative course was uneventful.

Effect of chromium(III) on nucleolar RNA synthesis

The enhancement of hepatic nucleolar RNA synthesis induced by Cr(III) in partially hepatectomized rats and its mechanisms are described. Cr(III)-administered (0.5 mg Cr/kg, ip) and then partially hepatectomized rats were significantly enhanced in the hepatic nucleolar RNA synthesis at the very early stage of liver regeneration. This enhancement was caused both by the induction of newly found nucleolar Cr-bound protein of 70 kD (Cr-p70) and by the activation of nucleolar chromatin, both of which arose from nuclear accumulation of Cr together with partial hepatectomy. Studies on the mechanism of this enhancement indicated that the Cr-p70 bound to the activated nucleolar chromatin and loosened its higher-order structure, resulting in an increase of the B-form fraction of chromatin DNA. The degree of this loosening well correlated with the amount of Cr-p70 bound to chromatin and also with the extent of elevation of RNA synthesis. Some molecular species of nonhistone proteins in chromatin were found to play an important role in the interaction to Cr-p70. These results suggest a possibility that the action of Cr is involved in cell proliferation process.

[Atrial septal defect with tricuspid valve regurgitation and heart failure in early childhood: report of a case with successful surgical management consisting of special patch closure technique and use of polydioxanone suture for the tricuspid annuloplasty]

A management of surgery for infant having a small left ventricular cavity associated with atrial septal defect and tricuspid valve regurgitation was presented. A right upper part of the defect was remained in open during a patch closure of ASD and this portion was temporarily sutured by prolene stayed extracardialy through Waterston's groove. During 20 minutes after weaning from the cardiopulmonary bypass, left heart failure did not appear and then it was completely closed. DeVega's method was employed for the tricuspid valve regurgitation using a absorbale Polydioxanone suture, because of a growth of the sutured annulus. Postoperative course was uneventful and trivial tricuspid valve regurgitation was recognized in angiocardiographic studies performed in 2 weeks and 6 months after operation.

[The results of surgical treatment of total anomalous pulmonary venous return in neonates]

By the time, the results of surgical treatment for total anomalous pulmonary venous return have been unsatisfactory. From 1981, we changed a surgical procedure fro Gersony-Malm procedure to the posterior approach method, and a surgical technique from the deep hypothermia and the circulatory arrest to the moderate hypothermia and the pump perfusion. Consequently, the results of surgical treatment was improved. From 1981 to 1987, 18 neonates with total anomalous pulmonary venous return underwent corrective operations in our institute. This diagnosis was decided by echocardiography without cardiac catheterization, because the preoperative status of these neonates were poor. Under the cardiopulmonary bypass, we performed the posterior approach method for type I and III, the cut-back method and Van Praagh procedure for II and IV without aortic clamping. According to the posterior approach method, the atrial septal defect was closed through the left atrial incision and the left atrium was anastomosed to the common pulmonary trunk during ventricular fibrillation. The incision was limited within the common pulmonary trunk or the vertical vein and was not extended into the pulmonary veins. According to cut-back method and Van Praagh procedure, the coronary sinus was closed internally so as to avoid the postoperative conduction disturbance. There were four hospital deaths (22.2%). The causes of deaths were pulmonary hypertension in two, low cardiac output in one, and intracranial bleeding in one. From the results of our institution, we concluded that the primary factors determining the outcome were the condition of the patients prior to repair and the severity of pulmonary hypertension.

A supernumerary valvula in the pulmonary semilunar valve

A supernumerary valvula of the pulmonary semilunar valve was found in a 51-year old, male Japanese. The valve was composed of three equal-sized valvulae and one smaller one with numerous fenestrations present. The supernumerary valvula was located between the anterior and right valvulae. We found this condition in one of 1407 cadavers examined.

[A monoclonal antibody study of carcinoembryonic antigen (CEA) in skin and skin tumors]

Using anti-CEA polyclonal antibody (PoAb), carcinoembryonic antigen (CEA) has been demonstrated immunohistologically in the sweat gland apparatus of normal human skin. Therefore, staining for CAE has been commonly used for the diagnosis of sweat gland tumors and sweat gland differentiation of the skin tumors. However, recently, various kinds of CEA-associated antigens which cross-react with anti-CEA PoAb have been found. It has been pointed out that anti-CEA PoAb is not specific to CEA and gives false positive reactions. In the present study, localization of CEA in normal skin and skin tumors was evaluated immunohistologically using anti-CEA PoAb and three kinds of anti-CEA monoclonal antibodies (MoAbs), which were more specific for CEA. From the studies with PoAb and MoAbs, it appeared that CEA-associated antigens were present in the area which reacted with PoAb and that eccrine glands contained various kinds of CEA-like substances. Pure CEA may not exist in skin tissues.

The elongation factor Tu.GTPase reaction: effect of 2'(3')-O-aminoacyl oligoribonucleotides

The activity of synthetic (2'(3')-O-aminoacyl trinucleotides, C-C-A-Phe, C-C-U-Phe, C-U-A-Phe, U-C-A-Phe and C-A-A-Phe, in promoting the EF-Tu.70 S ribosome-catalyzed GTP hydrolysis was investigated. It was found that the activity decreases in the order C-C-A-Phe greater than C-U-A-Phe greater than U-C-A-Phe greater than C-A-A-Phe much greater than C-C-U-Phe. Thus, the substitution in 'natural' C-C-A sequence with other nucleobases weakens binding of 2'(3')-O-aminoacyl trinucleotides to EF-Tu, with the substitution at the 3'-position having the most profound effect. Since the 2'(3')-O-aminoacyl oligonucleotides mimic the effect of the aa-tRNA 3'-terminus on EF-Tu.GTPase, it follows that EF-Tu probably directly recognizes structure of nucleobases in the aa-tRNA 3'-terminus, with the 3'-terminal adenine playing the most important role.

Mechanisms of potentiation of antitumor activity of 5-fluorouracil by ribothymidine in a mouse tumor system

In the presence of ribothymidine, the uptake of 5-fluorouracil (5-FU) was enhanced in Ehrlich ascites carcinoma cells in vitro, and was efficiently converted to FU-nucleotides. In these cells, almost all ribothymidine was found to be converted to thymine by, presumably, uridine phosphorylase. The enhanced uptake of 5-FU and its efficient conversion to FU-nucleotides were also observed in Ehrlich ascites carcinoma of ribothymidine-coadministered mice. The radioactivity of 5-FU-14C in the carcinoma cells, which was detected mainly in the acid-soluble fraction immediately after the administration and then shifted to the ribonucleic acid fraction, was approximately 2-fold higher in the ribothymidine-coadministered group than in the control group. On the other hand, ribothymidine-14C was also taken up by the carcinoma cells and an appreciable portion of its radioactivity appeared in the thymine fraction. Thymine produced from ribothymidine-14C was also detected in the extracellular ascitic fluid. The conversion of ribothymidine to thymine was assumed to be catalyzed by uridine phosphorylase, suggesting that ribose 1-phosphate was coproduced and served as a ribose donor for 5-FU. These results suggest that ribothymidine may act as a ribose donor for 5-FU to form FU-nucleotides via 5-fluorouridine in carcinoma cells, resulting in the potentiation of 5-FU activity.

Enhancement of antitumor activity of 5-fluorouracil by ribothymidine

The antitumor activity of 5-fluorouracil (5-FU) in combination with ribothymidine was examined on some experimental murine carcinomas. The antitumor activity of 5-FU against Ehrlich ascites carcinoma was markedly enhanced by intraperitoneal coadministration of ribothymidine. The enhancement of the antitumor activity of 5-FU by ribothymidine was also observed against Ehrlich solid carcinoma both by oral and intraperitoneal administrations. Furthermore, the combination therapy of 5-FU and ribothymidine was effective even on 5-FU-resistant P388 leukemia. These results suggest that the combination of 5-FU and ribothymidine may be more effective than 5-FU monotherapy in clinical use.

Quantitative fluorographic detection of 3H and 14C on two-dimensional thin-layer chromatographic sheets by an ultra-high-sensitivity TV camera system

A method for quantitative detection of 3H and 14C on thin layers is described. After impregnation of the TLC sheet with 50% 2,5-diphenyloxazole-tetrahydrofuran, quantitative imaging of the distribution of weak beta-ray-emitting isotopes on the chromatogram was carried out at room temperature by using a TV camera system, which consisted of a two-stage microchannel plate image intensifier, a low-lag vidicon, and an image processor. The method is applicable for 14C- and 3H-labeled samples on TLC sheets (10 X 10 cm) emitting more than 0.17 and 7.5 Bq/mm2, respectively. The method is rapid and has a dynamic range far greater than that of film.

Surgical treatment for infective endocarditis--decision tree for the treatment and introduction of translocation method

Persistent fever during active-phase IE is an indication for surgical treatment in the light of the causative organism and the underlying disease. To counter worsening hemodynamics, surgery may be the only feasible way. Surgery is performed when the patient does not respond to vasodilators and he shows an FS of less than 25%. The introduction of translocation provides a solution for the treatment of active IE. Lesions, vegetations more than 5 mm in diameter, periannular abscess, and mycotic aneurysm that could never be overlooked by two-dimensional echocardiography may hasten the early-stage decision of ways to treat IE.

Potentiation of the antitumor effect of 5-fluorouracil by some nucleotides, and their possible role in the potentiation

Of the various nucleotides tested, adenosine 5'-triphosphate (ATP), guanosine 5'-triphosphate, inosine 5'-triphosphate, and adenosine 5'-monophosphate potentiated the antitumor activity of 5-fluorouracil against Ehrlich carcinoma, while uridine 5'-triphosphate, cytidine 5'-triphosphate, deoxyadenosine 5'-triphosphate, and deoxyguanosine 5'-triphosphate were ineffective. The result of biochemical experiments suggests that ATP, which was used as a representative of the effective nucleotides, was ineffective until it was hydrolyzed to adenosine by nucleotide phosphohydrolases in the ascitic fluid of mice bearing Ehrlich ascites tumor cells, and that the adenosine functioned as a ribose donor for the increased formation of antineoplastic 5-fluoronucleotides. The possible role of the various effective nucleotides and nucleosides was discussed.

Antitumor effect of 5-fluorouracil in combination with some additives which stimulate the formation of antineoplastic 5-fluorouracil nucleotides

Both ribose 1-phosphate and deoxyribose 1-phosphate, which were effective in increasing the formation of antineoplastic fluoronucleotides and fluoro-RNA from 5-fluorouracil (5-FU) in the intact cells of Ehrlich mouse ascites tumor, potentiated the antitumor effect of 5-FU. Ethylenediaminetetraacetate, which stimulates the formation of only fluororibonucleotides from 5-FU in intact Ehrlich tumor cells, was ineffective in the potentiation of 5-FU antitumor activity. The relationship between the increased metabolite formation from 5-FU and the antitumor effect of 5-FU is discussed.

Increased uptake of 5-fluorouracil by Ehrlich ascites tumor cells with some additives and metabolite analysis

We studied the uptake of radioactive 5-fluorouracil (FUra) by the intact cells of Ehrlich ascites tumor in the presence of various coreactants with FUra such as uridine (Urd), deoxyuridine (dUrd), ribose 1-phosphate (Rib1P), and deoxyribose 1-phosphate (dRib1P). Radioactivity uptake by the cells was increased when FUra-6-14C was incubated with Rib1P or dRib1P, while the uptake was not stimulated with Urd or dUrd. The increased formation of antineoplastic ribo- and deoxyribo-nucleotides of FUra in the acid-soluble fraction was also observed in the same incubation with Rib1P or dRib1P. Also, some detergents, ethylenediaminetetraacetic acid (EDTA), adenosine 5'-triphosphate (ATP), and polyamines were examined. EDTA stimulated the uptake of radioactivity from the FUra by the cells. However, the other compounds exhibited no effect on the uptake of FUra alone or FUra plus dRib1P, except of ATP showing somewhat increase of radioactivity uptake. The above results suggest that the coadministration of FUra together with Rib1P or/and dRib1P, which are stimulants for the formation of FUra-deoxynucleotides from FUra, may be able to potentiate the chemotherapeutic effect of FUra.

Additive formation of antineoplastic 5-fluorouracil nucleosides from 5-fluorouracil by Ehrlich ascites tumor extracts in the presence of ribose 1-phosphate/uridine or deoxyribose 1-phosphate/deoxyuridine

In order to acquire a biochemical fundamental knowledge on the enhancement of antitumor effect with 5-fluorouracil or its masked derivatives, this investigation was undertaken to determine the amounts of antineoplastic metabolic precursors formed from 5-fluorouracil-6-14C in the presence of various substrates by crude enzyme extracts from Ehrlich mouse ascites tumor cells and normal mouse liver. Combinations of uridine plus ribose 1-phosphate and deoxyuridine plus deoxyribose 1-phosphate were effective for the enhancement of 5-fluorouridine and 5-fluorodeoxyuridine formation, respectively. 5-Fluorouridine and 5-fluorodeoxyuridine are respectively utilizable for the syntheses of the antineoplastic compounds, 5-fluorouridine 5'-triphosphate and 5-fluoro-2'-deoxyuridine 5'-monophosphate. These results suggest that the coadministration of the above substrates together with 5-fluorouracil would be advantageous in the enhancement of the antitumor effect of 5-fluorouracil or its masked derivatives.

Biochemical characteristics of a 5-fluorouracil-resistant subline of P388 leukemia

A 5-fluorouracil (5-FU)-resistant cell line of P388 mouse leukemia was established by intraperitoneal treatment with the drug. The activities of enzymes responsible for the formation of 5-fluoro-2'-deoxyuridine 5'-monophosphate and 5-fluorouridine 5'-monophosphate from 5-FU, the quantities of 5-FU metabolites, and the permeability to 5-FU were determined in both the 5-FU-sensitive and the resistant cell lines. It was found that the activities of uridine kinase and uracil phosphoribosyltransferase, the initial uptake of 5-FU, and the intracellular levels of 5-FU-nucleotides were all decreased in the resistant cells. However, the initial uptake of 5-FU into cells preincubated with KCN was the same in the sensitive and the resistant cells. These results support the view that the ineffectiveness of 5-FU against the resistant cell line of P388 leukemia can be attributed to decreases in the activities of enzymes responsible for the formation of 5-FU-nucleotides and probably also decreased transport of 5-FU in the resistant cells.

Elevation of the salvage synthesis of ribonucleic acid in the rat liver during the induction of hepatoma with 3'-methyl-4-(dimethylamino)azobenzene

Incorporation of uracil and orotic acid into the ribonucleic acid (RNA) fraction of rat liver during carcinogenesis induced with 3'-methyl-4-(dimethylamino)azobenzene was investigated. Uracil incorporation was found to be gradually elevated during the early stage (about 2 weeks) of the carcinogenesis, although not in the normal rat liver homogenates contacted with the carcinogen for a short hours, and the elevated uptake was maintained until tumor induction. On the other hand, orotic acid incorporation reverted to the original level after a temporary increase during the early stage. In a good agreement with the increased uracil incorporation, activities of both uridine phosphorylase and uridine kinase involved in the salvage pathway of RNA synthesis also increased during the early stage, and their activities in the liver were maintained at elevated levels after discontinuance of the carcinogen feeding. The activity of uridine monophosphate (UMP) pyrophosphorylase, converting uracil to UMP, was not detected during the early stage. Significance of the activation of the salvage pathway of RNA synthesis during the early stage of an axo dye-induced carcinogenesis were discussed.

[Radiolytic decontamination of Di-n-butyl phthalate from water (author's transl)]

Recently, a considerable amount of phthalic acid esters (PAE), the most widely utilized plasticizer, has been released into and polluted the environment. Since their toxicity and teratogenicity, although fairly low, to experimental animals have recently been shown, the removal of them from the environment, especially from the drinking water, is desirable. As an attempt for the removal, the radiolytic degradation of 7-14C-di-n-butyl phthalate (14C-DBP) in water was investigated at several pHs. Approximately 50% of 14C-DBP (1 ppm aqueous solution) was decomposed by 60Co gamma-irradiation to a dose of 3 X 10(4) rad at pH 7 and the main product was mono-n-butyl phthalate (MBP). At pHs 3 and 11 14C-DBP was more easily radiolyzed and converted to ether-soluble compounds other than MBP or phthalic acid (PA). By irradiation to 10(6) rad 14C-DBP as well as 14C-MBP and 14C-PA, at pH value tested, was almost completely decomposed to volatile or water-soluble substances of possibly low molecular weight. These findings suggest that the gamma-irradiation is effective to make the PAE-polluted water clean.